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Tuesday, June 28, 2011

DESIGN OF WIRELESS DATA MODEM


DESIGN OF WIRELESS DATA MODEM


EXPT NO: 4

AIM:

To communicate between two microprocessors using wireless data modems.

APPARATUS REQUIRED:
                    
          1.8085 microprocessor kit - 2
            2. Wireless data modem – 2

DESIGN:
         
Baud rate calculation:
Baud rate * Required baud rate input to 8251=  Required clock
16*300 = 4800
Therefore, Required clock input to 8251 = 4800 Hz
Count value = Clock input to 8253 / Required clock input to 8251
                        =1.536*10^6 / 4800
                   = 320 = 140 H.

HARDWARE DESCRIPTION OF VCT-10A


HARDWARE DESCRIPTION OF VCT-10B


ALGORITHM FOR TRANSMITTER:

  1. Initialize the serial port for data transmission.
  2. Set baud rate as 300.
  3. Initialize the memory pointer of the data to be transmitted.
  4. Set a counter for verification of EOF.
  5. Get the data from the consecutive memory locations and transmit it till EOF is reached.
  6. Reset the system.




































FLOWCHART FOR TRANSMITTER


PROGRAM FOR TRANSMITTER:

 

Address         Opcode      Label      Mnemonics     Operand         Comments
 

4100                  21,00,45                                    LXI             H, 4500H

4103                  3E, 36                                       MVI                        A, 36H   Set the timer

4105                   D3, 0B                                     OUT                                       0BH Channel 0 in mode 3

4107                 3E, 40                                                                             MVI            A, 40H            Set baud rate as 300

4109                    D3, 08                                     OUT             08H

410B                 3E, 01                                        MVI             A, 01H

410D                  D3, 08                                      OUT             08H

410F                   0E, 05           RELOAD             MVI          C, 05H                                 Load count

4111                   DB, 05            CHECK             IN              05H

4113                  E6, 04                                         ANI             04H                  Check transmitter empty

4115                 CA, 11, 41                                    JZ             CHECK

4118                  7E                                              MOV            A, M

4119                 D3, 04                                       OUT              04H

411B               23                                                INX               H

411C                 FE, 3F                                       CPI               3FH                    Check EOF

411E                C2, 0F, 41                                   JNZ            RELOAD

4121                 0D                                                  DCR          C

4122               C2, 11, 41                                   JNZ               CHECK
 

4125                     CF                                         RSTI                                            Reset





ALGORITHM FOR RECEIVER:

1.Initialize the serial port for data reception.
2.Set baud rate as 300.
3.Initialize the memory pointer for the data to be EOF.
4.Set a counter for verification of EOF.
5.Receive the data and store it in the consecutive memory locations till EOF is reached.
6.Reset the system.

FLOWCHART FOR RECEIVER







PROGRAM FOR RECEIVER:

 

Address         Opcode      Label      Mnemonics     Operand         Comments
 

4100                  21,00,45                                      LXI           H, 4500H

4103                  3E, 36                                         MVI           A, 36H              Set the timer

4105                   D3, 0B                                      OUT            0BH                  Channel 0 in mode 3

4107                 3E, 40                                                                               MVI  A, 40H        Set baud rate as 300

4109                  D3, 08                                         OUT           08H

410B                 3E, 01                                          MVI            A,01H

410D                  D3,08                                         OUT             08H

410F                   0E, 05           RELOAD              MVI           C, 05H                Load count

4111                   DB, 05            CHECK             IN              05H               Check receiver is ready
 
4113                  E6, 02                                       ANI 02
                                   
4115            CA, 11, 41                                       JZ                  CHECK             

4118               DB, 04 IN                                   04H
                                              
411A                77                                                MOV           M, A

411B                  23                                              INX                        H

411C                D3, 04                                                                               CPI           3FH                 Check EOF

411E                23                                                JNZ              RELOAD

4121                  FE, 3F                                       DCR             C                        

4122                0D                                                                                       JNZ           CHECK

4125                 CF                                              RSTI                                            Reset



TABULATION:


TRANSMITTER
RECEIVER
ADDRESS
INPUT
ADDRESS
OUTPUT





























RESULT:
Thus the communication between two microprocessors is made using wireless data modem.







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